For me to want to repeatedly play a game I like to have different experiences each time. You can have the same basic story but with different encounters/mechanics, or the same encounters/mechanics with different stories. Customisation in games really helps with this as you can change your play style and enjoy a game that way too. One way to change the experience every time is to have procedural/random generation – terrain, enemies, items, or just about anything you can think of. Using a computer doesn’t make generation random exactly – everything is determined by calculations – but it’s pretty close and gives the feel of randomness, which is more important. I used the video below to create a script for generating random coordinates within an area of my designation and for prefabs to spawn at those coordinates.
You can see it working in the video below. The white cubes are to show the corners of the spawn area. The script is setup so each element in the Enemy Types list will correspond to the same element number in the Enemy Spawn Counts list and will use the number in the spawn counts list to spawn the prefab in the types list that many times. The spawning coordinates are all random between the parameters set, and even the rotation can be changed.
I made a modified version of this so you can choose the points you want an object to spawn in, and it will choose an object randomly from the list given to it. I used this to spawn in weapons for the player to choose from to vary their experience more.